I had the correct path to git in Jenkins, but I had not yet accepted the Xcode build tools EULA on a fresh install of OS X Yosemite, so git looked like it was failing in Jenkins. After trying "git --version" on the git at /usr/bin/git in a terminal, I was given a command-line interface to accept the EULA, and then Jenkins could then access the git URL I had given the build project.

Another issue i faced with was, ssh.exe was not looking at the %userprofile%/.ssh folder for the key files. Instead it was looking to the folder C:\Program Files (x86)\Git\.ssh which was empty and which causes a hang due to ssh authentication prompt on the machine where git repo located.

We just copied the key files under %userprofile%/.ssh to C:\Program Files (x86)\Git\.ssh and the problem is resolved.

If you do not copy and paste the full file path addess e.g. C:\Program Files\Git\bin\git.exe, in the 'path to executable' field when configuring Git, it can lead to errors. Windows 8 & 10 for instance have a 'copy path' functionality which really works and helps to get full path name. Mac should have something similar. Its always best to use that rather clicking in the path address address bar and copying. This does not usually give the full file path and may cause a lot of troubles if you forget to edit the path at its destination.

Please install git in your Jenkins server. For example, if you are using Red Hat Enterprise Linux where you are hosting Jenkins, then install git in that server using the following command:
sudo yum install git
This should solve the problem as git executable will be available in /usr/bin/git then and this will be recognized automatically by jenkins and this you can verify by navigating to Manage Jenkins --> Global Tool Configuration. Then under Git installations, there will not be any warning and now you should be able to clone your git project in jenkins. Hope this help the users.